How mining affects Earth’s surface
|Published
Cape Town - A five-year study by a UCT PhD graduate has revealed that microwave imagery (radar remote sensing technology) captured from Earth-orbiting satellites can measure deformation in the Earth’s surface caused by underground mining.
Jeanine Engelbrecht said that by using satellites instead of field-based techniques to examine any (millimetre to centimetre) changes in the Earth’s surface, larger areas could be covered and it would be more cost-effective and less time consuming.
“The satellite data also ensures the early detection of deforming areas, based on which field-based investigations can be commissioned,” said Engelbrecht.
She said the main thrust of her research was to monitor how surface deformation, as a result of natural geological processes and underground mining, could have significant surface impacts and to find out the advantage of using satellite technology. She said the technique could be extended to any region undergoing deformation owing to mining.
“Surface deformation due to underground mining poses risks to health and safety, as well as infrastructure and the environment (unstable ground). Since the measurements are no longer based on point measurements in the field, the full extent of deforming areas can be recognised,” she said.
The process of microwave imagery uses microwave sensors on satellites or survey aircraft that transmit signals towards the Earth’s surface. A significant amount of information is gained from this process and it can cover vast amounts of land at a time.
There were four different satellites used in Engelbrecht’s research, including one from Canada, the German Aeronautic and Space Agency, Japan and the European Space Agency. She said there were still limitations to the technology related to signal noise, and that it should be used in conjunction with field-based techniques. - Cape Argus